Tank overflow risk mitigation system

Abstract

An overflow risk mitigation system for a large aboveground liquid storage tank includes a conduit mounted to an outside of the storage tank and extending from an overflow release port disposed in an upper portion of the storage tank to a lower portion of the storage tank. The conduit is closed and channels liquid overflow from the tank to a ground level while minimizing the production of mist or aerosol. The conduit can extend substantially vertically downward from the overflow release port, can have a cross sectional area substantially larger than that of the overflow release port and that expands downwardly from the release port, and can include a diffusive media at an outlet thereof. The overflow release port may be one of a plurality of release ports disposed at a same elevation around a periphery of the tank to allow for flow of liquid exceeding a maximum storage level.

What is claimed is: 
     
         1 . A tank overflow risk mitigation system, comprising:
 a conduit mounted to an outside of a liquid storage tank having a plurality of overflow release ports disposed in an upper portion of the liquid storage tank, the conduit extending between one of the plurality of overflow release ports and a lower portion of the liquid storage tank.   
     
     
         2 . The tank overflow risk mitigation system of  claim 1 , wherein the conduit extends substantially vertically downward from the one overflow release port along an outer surface of the liquid storage tank. 
     
     
         3 . The tank overflow risk mitigation system of  claim 1 , wherein the conduit has an upper portion located proximate to the one overflow release port and a lower portion proximate to the lower portion of the liquid storage tank, and a cross sectional area of the lower portion of the conduit is larger than a cross sectional area of the upper portion of the conduit. 
     
     
         4 . The tank overflow risk mitigation system of  claim 3 , wherein the cross sectional area of the lower portion of the conduit is at least 3 times larger than the cross sectional area of the upper portion of the conduit. 
     
     
         5 . The tank overflow risk mitigation system of  claim 1 , wherein the one overflow release port extends through a wall of the liquid storage tank and allows for flow of stored liquid exceeding a maximum storage level for the liquid storage tank, and the conduit directs the flow of the stored liquid exceeding the maximum storage level to a ground level outside of the liquid storage tank. 
     
     
         6 . The tank overflow risk mitigation system of  claim 1 , further comprising:
 a plurality of conduits including the conduit, each conduit of the plurality of conduits extending between a respective one of the plurality of overflow release ports and the lower portion of the liquid storage tank.   
     
     
         7 . The tank overflow risk mitigation system of  claim 6 , wherein each of the plurality of overflow release ports are disposed at a same height as each other in the upper portion of the liquid storage tank, and each conduit extends from one of the overflow release ports disposed at the same height as each other. 
     
     
         8 . The tank overflow risk mitigation system of  claim 6 , wherein a conduit is included for each overflow release port of the plurality of overflow release ports of the liquid storage tank. 
     
     
         9 . The tank overflow risk mitigation system of  claim 1 , wherein the conduit has a cross sectional area larger than an area of the one overflow release port. 
     
     
         10 . The tank overflow risk mitigation system of  claim 9 , wherein the conduit has a minimum cross sectional area at least 50% larger than an area of the one overflow release port. 
     
     
         11 . The tank overflow risk mitigation system of  claim 1 , wherein the conduit includes a three-sided structure attached to the outside of the liquid storage tank and forming a four-sided conduit for liquid flow using the three-sided structure and an outside surface of the liquid storage tank. 
     
     
         12 . The tank overflow risk mitigation system of  claim 1 , wherein the conduit includes a four-sided structure attached to the outside of the liquid storage tank. 
     
     
         13 . The tank overflow risk mitigation system of  claim 1 , further comprising a diffusive media disposed at an outlet of the conduit adjacent to the lower portion of the liquid storage tank. 
     
     
         14 . The tank overflow risk mitigation system of  claim 13 , wherein the diffusive media is disposed within the conduit and includes rocks of varying sizes. 
     
     
         15 . The tank overflow risk mitigation system of  claim 14 , wherein the conduit includes a grating at an outlet thereof disposed adjacent to the lower portion of the liquid storage tank, and the diffusive media is disposed on an inside of the conduit and of the grating. 
     
     
         16 . The tank overflow risk mitigation system of  claim 14 , wherein the diffusive media disposed adjacent to an outlet of the conduit has an average size larger than diffusive media disposed further from the outlet of the conduit. 
     
     
         17 . The tank overflow risk mitigation system of  claim 1 , further comprising an access hatch providing access inside the conduit along the outside of the liquid storage tank. 
     
     
         18 . The tank overflow risk mitigation system of  claim 17 , wherein the access hatch is disposed between 3 and 5 feet above a lower extremity of the conduit and has at least one dimension of 1 foot or larger. 
     
     
         19 . The tank overflow risk mitigation system of  claim 1 , further comprising a tube connected to the conduit and extending upward from the one overflow release port. 
     
     
         20 . The tank overflow risk mitigation system of  claim 19 , wherein the tube extends between 4 and 8 feet upward from the one overflow release port.